2005 Toyota Highlander TEMP INDICATOR OK BUT ONLY HOT AIR I

ALFRESKO

MEMBER
2005 TOYOTA HIGHLANDER
6 CYL
2WD
AUTOMATIC
43,000 MILES

When I'm driving, the engine indicator lights are fine, but hot air is blowing into the passenger cabin from the open vents. I mean REALLY hot air, so that one has to close off the vents completely.
If I try to use the air conditioner, it also blows only hot air into the cabin.
All fluid levels are fine, but I've never replaced the brakes. This problem happens even when I'm driving down the freeway, so I don't think it is a brake issue.
I did notice that the power steering fluid is a dark, dirty color. Again, the fluid level is fine.
I saw a minor amount of fluid residue around the coolant reservoir cap, but when I open up the radiator cap, the level is fine.
Any suggestions as to what the cause might be?
Thanks in advance for your help!

3 Replies

KHLOW2008

MECHANIC
41,814 POSTS

Hi alfresko,

Your HVAC control seems to be stuck in the heater position. You need to check the air mix vent door, linkages and actuators.

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Tuesday, September 30th, 2008 AT 12:11 PM

DRAKEIS

MEMBER
1 POST

I have a 2005 Toyota Highlander 4cyl, and I had the same problem. When I turned the heater temp dial, only hot air came out. I could see the amplifier (air mix servo) under the passenger side of the dash moving a little back and forth but staying in Hot mode. I thought it was going to be an expensive repair. It cost me $50 at the dealership to find out that the nut behind the air mix dial comes loose over time. I imagine that a dishonest repair shop would have tried to charge me $1,000 to change the heater control assembly, so I made out alright. To tighten the bolt, pull the temp control nob straight off. see #16 in the figure.